1. Field of the Invention
Disclosed is a photoresist composition and a method of forming a photoresist pattern using the photoresist composition. Specifically, disclosed in an embodiment is a photoresist composition capable of preventing a reverse-tapered shape of a photoresist pattern and a method of forming a photoresist pattern using the photoresist composition.
2. Description of the Related Art
A liquid crystal display (LCD) apparatus displays an image using optical and electrical properties of liquid crystal, such as an anisotropic refractive index and an anisotropic dielectric constant. Desirable characteristics of an LCD apparatus include lighter weight, lower power consumption, and lower driving voltage in comparison with other types of displays, such as a cathode ray tube (CRT) or a plasma display panel (PDP).
Generally, the LCD apparatus includes an LCD panel and a light source providing the LCD panel with light. The LCD panel includes a plurality of pixels and a plurality of thin-film transistors (TFTs). The pixels and the TFTs are formed using a photolithography process that employs a photoresist composition.
The photoresist composition can be classified as either a positive photoresist composition or a negative photoresist composition. When a negative photoresist composition is used for forming a fine pattern, the light energy in an exposure process is preferably lowered to reduce interference with an adjacent pattern from light diffraction. However, when the light energy in the exposure process is lowered, a lower portion of a photoresist film is not provided with sufficient light energy. Thus, a photoresist pattern can have a reverse-tapered shape, wherein the width of an upper portion of the photoresist pattern is greater than that of a lower portion of the photoresist pattern.
The photoresist pattern having the reverse-tapered shape can be easily damaged by external pressure, for example, by an increase in pressure applied when being dried during a manufacturing process.